JPH04146122A - Manufacture of pneumatic tire - Google Patents

Abstract

PURPOSE:To contrive an improvement in accuracy in uniformity of a tire along with an improvement in sticking accuracy, by a method wherein a central tread and a right and left shoulder treads obtained through molding by dividing into three are stuck by deviating phases of spliced positions of a circumferential direction of the tire of them. CONSTITUTION:A tread 5 divided into three is extrusion-molded beforehand into a center tread 5a, which is in almost a trapezoidal sectional form, and two shoulder treads 5b and in almost a uniform width. Then the shoulder treads 5b are stuck respectively to a shoulder parts Wb and then the center tread 5a is stuck to a crown part Wa of a carcass 1 of a tire along a circumferential direction of the tire. In this case, the center tread 5a and shoulder treads 5b are stuck by holding a fixed phase difference between a spliced position Xa of the center tread 5a and a spliced positions Xb of the shoulder treads 5b, 5b. Then a stitching roll 4 is moved on the same in a lateral direction from the center O of a widthwise direction of a tire, pressed against the same and sticking is performed. Uniformity on a spliced part can be improved by a dispersion of the spliced parts in this manner.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a pneumatic tire, and more particularly, to a method for manufacturing a pneumatic tire that improves the uniformity of splice positions in the tread. be.

[Conventional technology]

Conventionally, when molding an ultra-flat radial tire (with an aspect ratio of 50% or less), as shown in FIG. The stitching roll 4 is used to apply pressure while moving from the center 0 in the width direction of the tire in the left and right direction (in the direction of the arrow).

[Problem that the invention seeks to solve]

By the way, as mentioned above, the stitching roll 4 is of a type in which a plurality of rollers rotate while moving in the left-right direction from the center O in the tire width direction, so in the case of a wide tread, The elongation in the radial direction becomes uneven, causing deformation in part of the tire shoulder, which has a negative impact on tire uniformity.In addition, because two treads are attached, air pockets occur in part of the shoulder.
There is a problem in that it affects the molding accuracy of the tire, and there is also a problem in that the splice portion of the tread becomes uneven in the circumferential direction of the tire, affecting tire uniformity.

[Purpose of the invention]

This invention was devised in view of these conventional problems, and it improves tire molding accuracy, particularly tire tread attachment accuracy, and improves the uniformity of tread splices, thereby improving tire uniformity. An object of the present invention is to provide a method for manufacturing a pneumatic tire with improved accuracy.

[Means to solve the problem]

In order to achieve the above object, the present invention attaches a center tread among the three tread parts in the circumferential direction of the crown part of a molded tire carcass, and attaches shoulder trends to a part of the tire shoulder, respectively. The gist of this is to attach the center tread and the shoulder trend with their splice positions shifted in phase.

[Operation of the Invention] This invention is constructed as described above, and the tire tread is formed in advance by dividing it into three parts: a center tread that is attached to the crown part of the tire carcass, and a shoulder tread that is attached to a part of the left and right shoulders. By attaching the center tread and the left and right shoulder treads in a phase-shifted splice position in the tire circumferential direction, the accuracy of tire tread attachment is improved and the uniformity of the tread splices is improved. , it is possible to improve the accuracy of tire uniformity.

[Embodiments of the invention]

Hereinafter, the present invention will be described in detail based on the accompanying drawings.

Note that the same components as those in the conventional example are given the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows a cross-sectional view of a flat radial tire T according to the present invention, l indicates a tire carcass, and a breaker 2 and a tread 5 divided into three parts are successively pasted on this tire carcass 1. It is constructed by laminating layers.

The tread 5 divided into three parts is formed in the tire carcass 1 in advance.
A center trend 5a with a substantially flexible cross section to be attached to the crown part Wa of the tire and two shoulder treads 5b of approximately equal width to be attached to the left and right shoulder parts wb are extruded and formed into a tire carcass 1. After a center tread 5a is attached to the crown portion Wa of the tire, shoulder treads 5b, 5b are sequentially attached to a portion of the tire shoulder wb.

Next, a method for attaching the center tread 5a divided into three parts and the shoulder treads 5b, 5b on the tire carcass 1 will be specifically explained with reference to FIG.

First, the center treads 5a and 5b are attached to the tire shoulder part wb, and then the center tread 5a is attached.
As shown in FIG. 2, the crown portion W of the tire carcass 1
Paste it along the circumferential direction of the tire. In this case, as shown in FIG. 3, the splice position fXa of the center tread 5a and the splice position xb of the shoulder treads 5b, 5b are attached with a predetermined phase difference. Then, using the stitching roll 4 from above, the tire is moved from the center 0 in the width direction of the tire in the left and right direction, and is pressed and pasted.

In addition, as described above, the center tread 5a and the shoulder treads 5b, 5b are attached to the stitching roll 4.
When stitching each splice position, the splice position Xa and the splice position Xb are not at the same position, so by dispersing the splice positions in the tire circumferential direction of Trend 5, it is possible to improve the uniformity at the splice part,
This also makes it possible to improve the accuracy of tire uniformity.

In addition, center trend 5a and shoulder tread 5b
, 5b is not limited to the case where the center tread 5a is attached first as described above, but the shoulder treads 5b, 5b may be attached first, and in this case also, the splice of the center tread 5a Of course, the position Xa and the splice position Xb of the shoulder trends 5b, 5b may be out of phase with each other.

〔Effect of the invention〕

This invention applies a center tread among the three tread parts in the circumferential direction of the crown part of the tire carcass formed as described above, and also attaches shoulder treads to a part of the tire shoulder. and the splice position with the shoulder tread,
Because it is applied with a shifted phase, it has the effect of improving the uniformity of the tread splice in the tire circumferential direction and improving the accuracy of tire uniformity, and even when applying a wide tread. There is no uneven elongation in the radial direction, there is no problem of air pockets forming in a part of the shoulder, and there is no deformation of a part of the shoulder, which improves the molding accuracy of ultra-flat tires, especially the adhesion of the tire tread. This has the effect of improving accuracy and tire uniformity.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a flat radial tire embodying the present invention, Fig. 2 is a perspective view showing a method for attaching a tread divided into three parts in the tire circumferential direction, and Fig. 3 is a method for attaching a trend. FIG. 4, which is a plan view of a flat radial tire, is an explanatory diagram showing a conventional method for attaching a tread. ■... Tire carcass, 2... Breaker, 4...
Stitching roll, 5... Tread, 5a... Center tread, 5b... Shoulder tread, T.
・・Flat radial tire, Wa... Crown part, wb
...Shoulder part, Xa, Xb...Splice position.

Claims (1)

[Claims] The center tread of the three tread parts is pasted in the circumferential direction of the crown part of the molded tire carcass, and the shoulder treads are pasted on each shoulder part of the tire, and the splice positions of the center tread and the shoulder tread are determined. , a method for manufacturing a tire with a blank space, characterized in that the tire is pasted with a phase shift.